This invention pertains to equalizing current flow in a plurality of branch circuits. Such branch circuits are used in galvanic or electroplating baths in order to electroplate a plurality of articles simultaneously.
When a plurality of articles are simultaneously electroplated in an electroplating bath, the articles are all hung from a common bench. It is known that the current density about the object so electroplated can vary as a result of, e.g., unequal distances of the objects from the anodes through which direct current is caused to flow. Additionally, it is known that when a large bench is utilized, the current density about objects in the middle of the bench is lesser than the current density about objects at the edge of the bench. In the event that the objects do not move in a fully symmetrical fashion, variation in current density can only be amplified. Moreover, it is possible that the connections between the objects which are to be electroplated and the bench or the anodes may not all be equally good. As a result of variation in the resistances of such connections, or in variations in resistance within an anode basket, variations in current density can also arise.
Regardless of the cause of variation of current density within an electroplating bath, such variations in current density result in varying precipitation speeds and therefore result in variations in thickness of the electroplated layer which is electroplated onto each of the objects. For planar objects, the two sides of the object may be plated with electroplating of varying thickness. In practice, this is most unsatisfactory and results in an unacceptable manufacturing expense, especially in the case of electroplating baths which electroplate objects with layers of precious metals.
Therefore, it would be advantageous to provide a system and a method which would equalize current flow in a plurality of branch circuits such as are used in an electroplating or galvanic bath which is designed to electroplate a plurality of articles simultaneously, to prevent variation in current density from arising and thereby equalize precipitation speed from object to object in the electroplating bath.